243 Ackley Improved Problems

Sir, knowing who you you are, I have to respectfully disagree.

Any 243 AI gauge that is made properly is designed to be a couple thou under at the shoulder/neck junction to headspace on the shoulder junction of regular 243 Win brass. That is after all what Ackley intended for all of his chamberings: The ability to fire "regular" cases, and the ability of the "regular" cases to headspace on the neck/shoulder junction.

I did buy an AI GO gauge when I installed the barrel on my savage, and one can certainly detect some load on the cam when chambering factory 243 Win brass, as intended. This load is of course not present after fireforming.

Your comments give me the impression that you have not used a "real" Ackley GO gauge, since all the concerns you raise with it are bogus. Most of the time it is tough to obtain the Ackley gauges and Manson is the only company I am aware of that generally has them in stock for the same price as any other gauge.

J E Custom said:

Sorry to disagree but the reason that you use a standard 243 Head space gauge is so that you can fire form 243 AI safely and without excessive head space.

If you use a standard 243 head space go gage It should seat the case at the neck shoulder junction
and hold the case in place.

It is recommended that when head spacing you actually have about .003 to .004 crush on the standard case. this also minimizes neck shortening.

The AI head space gage uses the datum line and the standard 243 case has a different datum
line because of the shoulder angle and will have to much head space if you fire a standard 243 round in it. once fire formed, or if you buy 243 AI ammo it is fine.

Some Fire form using the bullet against the lands to maintain head space but the bullets have to be seated farther out and pressures become an issue.

So, If you chamber with a 243 AI reamer and buy pre formed brass or loaded ammo then it is recommended that you use the 243AI head space gauge.

If you use a 243 AI reamer to chamber with but you want to shoot standard 243 ammo in it and fire form at the same time head space the AI chamber with the standard 243 head space gage.

After fire forming, the 243 AI dies will work fine and can be adjusted to fit the chamber.

J E CUSTOM
to

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J E Custom said:

Sorry to disagree but the reason that you use a standard 243 Head space gauge is so that you can fire form 243 AI safely and without excessive head space.

If you use a standard 243 head space go gage It should seat the case at the neck shoulder junction
and hold the case in place.

It is recommended that when head spacing you actually have about .003 to .004 crush on the standard case. this also minimizes neck shortening.

The AI head space gage uses the datum line and the standard 243 case has a different datum
line because of the shoulder angle and will have to much head space if you fire a standard 243 round in it. once fire formed, or if you buy 243 AI ammo it is fine.

Some Fire form using the bullet against the lands to maintain head space but the bullets have to be seated farther out and pressures become an issue.

So, If you chamber with a 243 AI reamer and buy pre formed brass or loaded ammo then it is recommended that you use the 243AI head space gauge.

If you use a 243 AI reamer to chamber with but you want to shoot standard 243 ammo in it and fire form at the same time head space the AI chamber with the standard 243 head space gage.

After fire forming, the 243 AI dies will work fine and can be adjusted to fit the chamber.

J E CUSTOM
to

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listen to "JE", as he's telling you the right way to setup the headspace in an Ackley chamber. Parker always set the chambers up the be somewhat tight at the junction of the neck to shoulder. By doing it this way you can still shoot standard generic .243 Win. in that chamber.

Now the O.P.'s chamber maybe reamed out of spec, or maybe it's a .264" necked chamber. We don't know because we don't have it in front of us! Myself presented with this situation, the first thing I'd do is to pull the barrel for a better look see. If I don't physically see something wrong in the chamber, I would probably do a chamber cast. The chamber cast done right will also show me what the throat looks like. Is it reamed somewhat short to fit 70 grain bullets? (I don't think this is the problem).

Here's some things you could do:

* take a couple factory sized .243 cases, and neck turn them down to about .262" in diameter. If the cases will chamber, you might have a tight necked chamber. If so you'll be neck turning every case (no big deal)

* This part is a little tricky, so bear with me. If you have a Stoney Point gauge or the newer Hornaday gauge you have the tool to start with. You really need two bushings, and a modified case. Myself, I'd would want on that's about .002" / .005" larger than the neck diameter of the case. Plus another that's about .370"/.375" bushing. With the modified case, you may well find the neck diameter a little undersized (my 6mm case is for sure). Will the modified case chamber? If it does, I'd be looking at the neck diameter. With the barrel removed, I'd try to put a full length sized case in the chamber ( factory).

You could simply break down a factory load, (kill the primer) and set the die up to push the shoulder back about .005". Will it chamber? If not push that shoulder back another .005". If it still won't chamber, I'd be doing a barrel set back with a new chamber. I know some guys that will push a shoulder back as much as .015", and glue plastic shims to the face of the case to get the head space number. The chamber may well have been reamed short, or at least in the very minimum side. Are you sure it's an Ackley chamber and not a .243 Rockchucker? They are similar, but one uses a 30 degree shoulder. That's why I'd do a chamber cast just to know what I have!
gary

westcliffe01 said:

Sir, knowing who you you are, I have to respectfully disagree.

Any 243 AI gauge that is made properly is designed to be a couple thou under at the shoulder/neck junction to headspace on the shoulder junction of regular 243 Win brass. That is after all what Ackley intended for all of his chamberings: The ability to fire "regular" cases, and the ability of the "regular" cases to headspace on the neck/shoulder junction.

I did buy an AI GO gauge when I installed the barrel on my savage, and one can certainly detect some load on the cam when chambering factory 243 Win brass, as intended. This load is of course not present after fireforming.

Your comments give me the impression that you have not used a "real" Ackley GO gauge, since all the concerns you raise with it are bogus. Most of the time it is tough to obtain the Ackley gauges and Manson is the only company I am aware of that generally has them in stock for the same price as any other gauge.

Click to expand...

To disagree is our right and all I can say is I have done several dozen AI chambers with both the standard go gauges and the AI go gages and my way has worked very well and all of the AIs have shot well under 1/2 MOA while fire forming.

I also have read everything I could find about PO ACKLEY to understand what he was trying to do
with the modified chamber.

He never intended for a AI chamber to be head spaced with a special head space gauge only the parent case head space. "BUT" once someone changes the case length dimensions (Like Nosler
Did) I has been screwed up ever since.

Now that the 280 AI has been standardized by SAMME the reamer makers have to make the NEW
head space gauge For the SAMME spec. ammo.

But all of the other AIs still have the Ackley dimensions.

I respect your opinion and if I don't agree with it so be it.

I will always head space the way I have described because I works and maintains Proper head space
avoiding case head separation and splitting.

The plus side to My way is it adds the .014 thousandths to the case that the AI head space gauge
does not and does what PO Ackley intended in the first place. (To be able to safely fire parent ammo in the chamber.

Note: To confirm this talk to the man that made the reamers for Nosler (Dave Kiff) and informed them of the problems they had created.

Thanks for your respect and the feeling is mutual.

J E CUSTOM

I'm not savy enough to get involved in this debate but I have a question as to what Nosler did to their 280AI so that it is different from the Ackley that was mentioned in the last post. I have a 280AI barreled by Gordy Gritters in IA. Not that I need to buy AI brass but if I came across some Nosler are you telling me it would not fit?

Maybe these guys didn't get it right, but according to the drawings, there is a 0.004" difference in dimension (shorter on the Ackley) from base to neck/shoulder junction. That 0.004" would be to insure that one headspaces on the neck/shoulder junction when one chambers regular 243 Win brass. The extra case volume is accomplished by blowing the shoulder forward and removing a little taper.

pinetree97814 said:

I'm not savy enough to get involved in this debate but I have a question as to what Nosler did to their 280AI so that it is different from the Ackley that was mentioned in the last post. I have a 280AI barreled by Gordy Gritters in IA. Not that I need to buy AI brass but if I came across some Nosler are you telling me it would not fit?

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It would fit, but that is the problem.

The Nosler brass and chamber dimension are .012 to .014 shorter than the original AI chamber
And if you shoot Nosler pre formed brass or ammo you end up with excessive head space in an "Original" chamber.

Talk to Gordy and find out if he used the "New" SAMME reamer and Head space gauge or if he head spaced with a standard 280 head space gauge.

Some people have fired the Nosler brass in the standard chambers and have not had any problems Others have had lots of problems.

All other AI chambers should be Ok.

J E CUSTOM

Thanks for the info JE. My rifle was done in 1994 so probably is fine. It is amazing to me that Nosler would change the specs like that. If it ain't broke.........

pinetree97814 said:

Thanks for the info JE. My rifle was done in 1994 so probably is fine. It is amazing to me that Nosler would change the specs like that. If it ain't broke.........

Click to expand...

After talking to Dave Kiff 0f PT&G (Who made the reamers for Nosler) It was my understanding
that they changed the dimensions on the chamber drawings without Dave's input And the problem was not found untill many chambers were cut and the drawings were submitted to SAMME .

J E CUSTOM

J E Custom said:

To disagree is our right and all I can say is I have done several dozen AI chambers with both the standard go gauges and the AI go gages and my way has worked very well and all of the AIs have shot well under 1/2 MOA while fire forming.

I also have read everything I could find about PO ACKLEY to understand what he was trying to do
with the modified chamber.

He never intended for a AI chamber to be head spaced with a special head space gauge only the parent case head space. "BUT" once someone changes the case length dimensions (Like Nosler
Did) I has been screwed up ever since.

Now that the 280 AI has been standardized by SAMME the reamer makers have to make the NEW
head space gauge For the SAMME spec. ammo.

But all of the other AIs still have the Ackley dimensions.

I respect your opinion and if I don't agree with it so be it.

I will always head space the way I have described because I works and maintains Proper head space
avoiding case head separation and splitting.

The plus side to My way is it adds the .014 thousandths to the case that the AI head space gauge
does not and does what PO Ackley intended in the first place. (To be able to safely fire parent ammo in the chamber.

Note: To confirm this talk to the man that made the reamers for Nosler (Dave Kiff) and informed them of the problems they had created.

Thanks for your respect and the feeling is mutual.

J E CUSTOM

Click to expand...

I realize this is an old thread, but I am just about to set the headspace on my 243 AI. The question I have is if I set the headspace to the 243 win go/no go gauges would it need changed after all my brass is fire formed? I have the 243 AI head space gauges being made right now as I was under the impression I needed special gauges.
Admittedly when I was told by PTG I needed a special gauge I was confused as I thought the whole idea of the AI cartridges was to be able to use the regular ammo and also the improved without any issue. I had a rifle set in 243 AI from before but I didn't set the headspace a gunsmith did. Anyway for me to determine how it was headspaced from the fired unsized brass? It shot lights out.

pinetree97814 said:

Thanks for the info JE. My rifle was done in 1994 so probably is fine. It is amazing to me that Nosler would change the specs like that. If it ain't broke.........

Click to expand...

Before Spec 280AI, Sierra and Nosler manuals had loading data for 280AI and if you have copy of Sierra manual, it may be what you have. I have Nosler manual 5 2002 and max load for 280AI with 150gr is 63gr/IMR-7828 @ 3107 fps and Nosler manual 8 has same max load for the Spec 280AI rest of loads maybe 1/2gr difference. Some of that could be different test barrel.

I think there was more people upset that didn't own 280AI. It sure didn't bother me. I have both. In Nosler manuals 5&8 they tell you how to fireform 280 brass and I think because Nosler/Sierra had loading data everyone assume used same dies. Nosler had reamers already for the none spec 280AI and Sierra did also.

Only thing Nosler did was blow case out little more but kept same case length.

morning, LISTEN TO JE CUSTOM. KNOWS WELL WHAT WORKS.
GBOT TUM

This has come up many times and will probably never be agreed upon but it can make a difference if it is done the way PO Ackley designed and intended for it to be.

Most if not all of the AIs are set up to use the standard headspace gauge for that cartridge with only one exception The 280 AI is done either way depending on the brass you intend to use. if you want to use standard 280 ammo and brass to fire form, you should use the standard headspace gauge with .004 thousandths crush fit to hold the brass in place while it is fire formed. If you intend to use new Ackley brass (It is formed to fit the new SAMME specification which is.014 to .016 thousandths longer than the standard 280 remington) and if you fire form standard 280 brass or ammo there is a possibility of case head separation from to much head space.

All other Ackley's except the wild cat versions are done using the standard head space gauges with the crush fit (.004).that uses the neck shoulder junction for this measurement instead of the Datum line normally used in shouldered cases.

As far as closing the bolt, .004 thousandths does not produce much resistance to closing. It essentially take out any slack in the head space and prevents the case from growing or moving very much while fire forming. it also makes the fire forming of parent cartridges very accurate and usable for hunting instead of taking the extra step to fire form and then load for hunting.

If you choose to buy an AI headspace gauge for anything "But" the 280 AI it should have this compression built in and will be .004 thousandths shorter at the neck shoulder junction to accomplish the same tight fit on the standard cartridge for fire forming.

J E CUSTOM

If your posting about me, everything I posted is true I'm just surprise JE didn't mention those 280AI in Nosler and Sierra manual and that's what my non Spec 280AI is. Those loads been in Nosler manual since mid 90's. I think it would be interest if JE post reamer print on the 280AI he build before spec

J E Custom said:

This has come up many times and will probably never be agreed upon but it can make a difference if it is done the way PO Ackley designed and intended for it to be.

Most if not all of the AIs are set up to use the standard headspace gauge for that cartridge with only one exception The 280 AI is done either way depending on the brass you intend to use. if you want to use standard 280 ammo and brass to fire form, you should use the standard headspace gauge with .004 thousandths crush fit to hold the brass in place while it is fire formed. If you intend to use new Ackley brass (It is formed to fit the new SAMME specification which is.014 to .016 thousandths longer than the standard 280 remington) and if you fire form standard 280 brass or ammo there is a possibility of case head separation from to much head space.

All other Ackley's except the wild cat versions are done using the standard head space gauges with the crush fit (.004).that uses the neck shoulder junction for this measurement instead of the Datum line normally used in shouldered cases.

As far as closing the bolt, .004 thousandths does not produce much resistance to closing. It essentially take out any slack in the head space and prevents the case from growing or moving very much while fire forming. it also makes the fire forming of parent cartridges very accurate and usable for hunting instead of taking the extra step to fire form and then load for hunting.

If you choose to buy an AI headspace gauge for anything "But" the 280 AI it should have this compression built in and will be .004 thousandths shorter at the neck shoulder junction to accomplish the same tight fit on the standard cartridge for fire forming.

J E CUSTOM

Click to expand...

Let me ask you a question. You talked to Dave Kiff so you knew about the Nosler 280AI so let me ask what chamber reamer did you use.